Terrorism -- 61 Prevention. -- 30 Prevention -- 29 Government policy -- 21 National security -- 17 Foreign relations -- 9 Prevention 9 more ... War on Terrorism, 2001-2009 9 Civil defense -- 8 Politics and government -- 7 Civil rights -- 5 Security measures 5 Terrorists -- 5 Emergency management -- 4 History -- 4 Islam 4 Religious aspects -- 4 Security measures -- 4 Terrorism 4 Aeronautics, Commercial -- 3 Defenses 3 Evaluation. -- 3 Intelligence service -- 3 Military policy 3 Politics and government 3 September 11 Terrorist Attacks, 2001 3 War on terrorism, 2001- 3 Counterinsurgency -- 2 Economic sanctions, American 2 Foreign relations 2 less ...